1. Field of the Invention
The invention relates to novel alkylenedioxythiophenes having urethane-containing side groups, to their preparation and to their oligo- and polymeric derivatives (oligo- and poly(alkylenedioxythiophene)s).
2. Brief Description of the Prior Art
The class of π-conjugated polymeric compounds has been the subject matter of numerous publications in the last few decades. They are also referred to as conductive polymers or as synthetic metals. Owing to the considerable delocalization of the π-electrons along the main chain, these polymers exhibit interesting (non-linear) optical properties and, after oxidation or reduction, and are also good electrical conductors. These compounds will consequently probably take on a leading and active role in various fields of practical application, for example in data storage, optical signal processing, suppression of electromagnetic interference (EMI) and solar energy conversion, and also in rechargeable batteries, light-emitting diodes, field-effect transistors, circuit boards, sensors and antistatic materials.
Examples of known π-conjugated polymers include polypyrroles, polythiophenes, polyanilines, polyacetylenes, polyphenylenes and poly(p-phenylene-vinylenes). A particularly important and industrially utilized polythiophene is poly-3,4-(ethylene-1,2-dioxy)thiophene which, in its oxidized form, has very high conductivities and is described, for example, in EP 339 340 A2. An overview of numerous poly(alkylenedioxythiophene) derivatives, in particular poly-3,4-(ethylene-1,2-dioxy)thiophene derivatives, their monomers, syntheses and applications is given by L. Groenendaal, F. Jonas, D. Freitag, H. Pielartzik & J. R. Reynolds, Adv. Mater. 12 (2000) 481-494. In U.S. Pat. No. 5,111,327 substituted 3,4-alkylenedioxythiophenes and also their conductive polymerization products are described.
Very high conductivities are also achieved by the methodology of in situ polymerization, in which the monomeric 3,4-(ethylene-1,2-dioxy)thiophene is reacted with oxidizing agents, for example iron-III tosylate, in solution to give a highly conductive layer of oxidized poly-3,4-(ethylene-1,2-dioxy)thiophene. This procedure is utilized, for example, for producing capacitors.
Despite the good properties of poly-3,4-(ethylene-1,2-dioxy)thiophene with regard to conductivity and processability, there is a need for further improvements, for example in conductivity, without impairments or even with improvements in colour and transparency, in electrochromic or else in mechanical properties.
Surprisingly, this object is achieved by the present invention.